The Study On Preparation And Properties Of Thermal Stimulus-responsive Composites Based On Eucommia Rubber

Shape memory polymers are a novel type of functional polymer material.SMPs can change their shapes and keep under certain conditions.After being stimulated by external conditions(such as heat,light,electricity,and chemical induction),they can recover their initial shapes.In this paper,we prepared a series of thermo-induced shape memory composites using eucommia gum(TPI)as the matrix material.We studied the vulcanization properties,mechanical properties,crystallization properties,and shape memory properties of composites,in order to explore the effect of microstructure on macro performance of composites.Details on research contents were represented as follows:First,we investigated the effects of blending ratio on the properties of TPI/NR shape memory composites.The results showed that the tensile strength and hardness of the system were reduced with the increase of NR content,and the change of elongation at break showed the different trend.At the same time,we explored the effect of crystalline small molecules stearic acid and paraffin on the properties of TPI/NR and TPI shape memory composites.We found that the addition of stearic acid and paraffin could improve the shape fixation rate of TPI/NR and TPI system.However,the shape recovery rate of the system decreased with the increase of stearic acid content.The addition of paraffin could also improve the shape fixation rate of the system.Meanwhile,the shape recovery rate of the system gradually decreased with the increase of paraffin content.Secondly,we investigated the effects of CNTs and CB content on the properties of NR/TPI shape memory composites.The results showed that: the tensile strength and hardness of the composites increased significantly with increase of CNTs and CB content,while the elongation at break showed a first increase and then decrease trend with the increase of filler content.When CNTs and CB was 2 phr and 10 phrrespectively,the elongation at break of the system reached a peak.At the same time,the addition of CNTs and CB could reduce the crystallinity of TPI in the system.In the shape memory performance,the shape fixation rate of the composites decreased due to the decrease of crystallinity in TPI phase.The effect of CNTs on the shape fixation rate in NR/TPI composites was greater than that of CB.The shape recovery rate of composites also decreased with the increase of reinforcing filler content.Finally,we investigated the effects of foaming agent AC and vulcanizing agent DCP on the properties of foamed TPI shape memory composites.We found that: the tensile strength and elongation at break of composites decreased with the increase of AC content.At the same time,the volume expansion rate of the composites increased and the density and hardness decreased with the increase of AC content.The crystallinity of TPI decreased slightly with the increase of AC content.For the shape memory performance,the shape fixation rate and shape recovery rate of the composites both increased with the increase of AC content.We then explored the effect of DCP on the properties of composites.The tensile strength and hardness of the composites increased significantly with the increase of DCP content.And the elongation at break first increased and then decreased with the increase of DCP content.The increase of vulcanizing agent DCP could reduce the volume expansion rate of composites and increase the density of composites.Meanwhile,the crystallinity of TPI decreased with the increase of DCP content.In the shape memory performance,the shape fixation rate of composited decreased and the shape recovery rate increased with the increase of DCP content.When the dosage of DCP was 1.0 phr,the shape recovery rate of composites reached 100%.